Skywarn is a free storm spotter training program hosted by the National Weather Service. The classes -- which are aimed towards the public -- usually last around two hours and are hosted prior to the start of severe weather season every year.
Skywarn participants learn a great deal about severe weather in general, but are also trained to look for weather elements that most of us wouldn't usually watch for -- cloud patterns, etc.
In addition to a standard lecture and question-and-answer sessions, participants can also usually obtain a variety of reference material that can be referred back to throughout severe weather season.
SKYWARN IN THE BRAZOS VALLEY
SKYWARN IN TEXAS